Area Forecast Discussion
Issued by NWS Brownsville, TX

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198
FXUS64 KBRO 200523 AAB
AFDBRO

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1123 PM CST Mon Feb 19 2018

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...Brisk southerly winds will continue overnight and
through the daytime on Tuesday. Some gusts will approach 30kts
from time to time. The other story will be a low stratus deck
sitting over our terminals this evening and into the Tuesday as
well. MVFR conditions initially will decline a bit to perhaps IFR
overnight and through the morning hours for BRO and HRL. There
should be some slight improvement by late morning. MFE has the
best potential for VFR Tuesday afternoon. The stratus deck
eventually lowers back to MVFR toward the end of this cycle.

&&

.PREV DISCUSSION... /issued 536 PM CST Mon Feb 19 2018/

..00z Aviation Update...

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...A fairly active TAF cycle ahead, especially tonight.
First, winds will begin to subside slightly this evening, however,
gusts of 20kts at times will still be possible as a strong
pressure gradient remains. A low stratus deck will also bring
conditions down from VFR to IFR later tonight for HRL and BRO.
Low end MVFR can be expected for MFE. Flight conditions should
slowly improve tomorrow (MVFR east and VFR for MFE). Another
breezy day is expected with southerly winds gusting up to 30kts.

PREV DISCUSSION... /issued 238 PM CST Mon Feb 19 2018/

LONG TERM (Wednesday through Monday): A weak cold front will push
into the CWA on Wednesday, mainly affecting the ranchlands and brush
country with showers and thunderstorms, though more so Wednesday
night. Can`t rule out thunder for the Lower Valley (LV), but the
boundary will struggle to make it all the way through, and mid level
ripples in the flow will likely not be enough to break the cap for
deeper convection over the LV. Model guidance is also less certain
with LV thunder so will maintain or reduce coverage slightly from
the inherited package. Not expecting any drastic change in temps with
the front. High temps will be a few degrees lower on Thursday, but
still above average. Return flow should redevelop on Thursday as a
West Coast short wave trough pushes into the Southwest, supporting
pressure falls over the southern High Plains, with rain chances
decreasing late in the week as the remnant front retreats north.

A second, slightly deeper short wave trough will dive south out of
the Pacific Northwest late in the week, and into the Southwest by
Friday. This time a surface front will push through Saturday night,
but the mid level trough will again be well to the north by then,
unable to provide strong upper dynamics. Moderate north to northeast
winds will develop on Sunday behind the front. All in all, did not
make a whole lot of changes to the inherited forecast.

MARINE:
Now through Tuesday Night: Surface/Buoy obs near the lower TX
coastline in addition to a recent ASCAT satl pass over the region
around 18z indicates that the surface winds are pushing into SCA
levels for the Bay waters but are struggling to reach SCA criteria
for the offshore waters this afternoon. A strong PGF persists across
the lower TX coastline today, but the downward mixing of the LLJ has
been limited due to fairly cool surf water temps near 60. As the
marine air temp cools down somewhat later tonight this could weaken
the low level marine inversion to allow some stronger winds to mix
down to the surface. So the SCA for Winds for the Gulf waters will
likely need to be extended through the overnight hours into Tues
morning. The PGF will then start to weaken somewhat throughout the
day Tues and into Tues Night which may reduce the chances for more
SCA conditions.

Wednesday through Saturday night: Moderate southeast to south winds
and moderate seas will prevail through the long term forecast as high
pressure to the east dominates the Gulf. A cold front will push
close to the coast on Wednesday, but is currently forecast to pull up
short of the Gulf waters. Small craft should exercise caution
conditions may develop from time to time.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until noon CST Tuesday for GMZ150-155-170-
     175.

&&

$$

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